PRIMARY DYSMENORRHOEA AND VASOPRESSIN

Abstract

Summary The circulating concentrations of arginine vasopressin on day 1 and on day 5 to 7 of the menstrual cycle were measured by radioimmunoassay in six women with primary dysmenorrhoea and five controls. All women had ovulated in the previous cycle, as indicated by the mid‐luteal phase plasma progesterone levels and had normal plasma osmolality and sodium concentrations. The plasma concentrations of progesterone and oestradiol on day 1 of the cycle were also measured, and no significant difference between the two groups was seen. In women with dysmenorrhoea the vasopressin concentration on day 1 was 0.400.038 (SE) μU/ml which was significantly higher than the concentration in normal women on the same day of the cycle 0.20±0.063 (SE) μU/ml (p <0.01). The plasma concentration of vasopressin in normal women on day 5 to 7 was 0.68 0.119 (SE) μU/ml which was significantly higher than on day 1 (p <0.01). A significant difference between day 1 and day 5 to 7 was not seen in dysmenorrheic women, possibly because the values were already elevated on day 1. The results suggest that vasopressin could be a factor of aetiological importance in primary dysmenorrhoea, and also indicate that the vasopressin concentration in plasma can vary according to the day of the menstrual cycle.